<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src='./lib/jquery-3.1.0.min.js'></script>
    <!-- <script>
        function hello(data){
          console.log("front_server==>>",data)
        }
 
     </script> -->
    <!--script是没有跨越的问题  -->
   <!--  <script src='http://localhost:4000/test.js'></script> -->
   <!-- <script src='http://127.0.0.1:4000/show?callback=hello'></script> -->

</head>
<body>

       <button>发送ajax</button>
</body>
</html>
<script>
      $("button").click(()=>{
          //alert("aaa");
       /*  $.ajax({
             type:"get",
             url:"http://127.0.0.1:4000/show",
             dataType:"jsonp",
             jsonpCallback:"getDatas",//给传入到后台的函数自定义的名字
             success:(data)=>{
                console.log(data);
             }
          }) */

         //使用代理服务区的方法
          /* $.ajax({
             type:"get",
             url:"/api/show",
             dataType:"json",
             success:(data)=>{
                console.log(data);
             }
          }) */
          
          $.ajax({
             type:"post",
             url:"/api/login",
             //传到后台的数据
             data:{
                "username":"abc11",
                "pwd":"abc123"
             },
            dataType:"json", //把json格式的字符串转为json对象
            success:(data)=>{
                 console.log(data);
              }
   })
      })
</script>